#define TRIG 2
#define ECHO 15
#define LED 12

float distance;
void readDistance(){
  digitalWrite(TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG, LOW);

  int duration = pulseIn(ECHO, HIGH);
  distance = duration * 0.034 / 2;
  }

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
  pinMode(LED, OUTPUT);

  digitalWrite(LED, LOW);
}

void loop() {
  // put your main code here, to run repeatedly:
  readDistance();
  if(distance > 100 && distance <= 150){
    digitalWrite(LED, HIGH);
  }else{
    digitalWrite(LED, LOW);
  }
}